Atmospheric Effects Testing

Military aircraft must function in all weather environments. The electromagnetic threats produced in such environments include lightning, Electrostatic Discharge (ESD) and Precipitation Static (P-Static). The effects caused by these threats include high-current transients lightning, high-voltage transients (ESD), and EMI (P-Static). These natural electrostatic effects can cause severe and unexpected degradation to aircraft and mission systems as well as hazards to crew personnel.

The Lightning Laboratory provides simulator capabilities that conduct full-scale aircraft and weapons systems tests. Full threat indirect lightning phenomena can be investigated as required by MIL-STD-464.

A high voltage transient generator is used to evaluate coupling of ESD into the aircraft and weapon systems.  Test capabilities include a standard 5 kV/25 kV human body ESD simulator and a 300 kV helicopter vertical replenishment ESD simulator.

A localized, high voltage static charge generator is used to evaluate P-Static EMI on aircraft receivers and instrumentation. The test equipment includes a portable P-Static generator test set and accompanying equipment to identify and investigate P-Static problems. The test set is used for both passive and active tests to determine EMI source locations and measurements of EMI thresholds. These tests are used to determine compliance with MIL-STD-464. The P-Static test set also provides a quick means to identify inadequately bonded areas on the aircraft.

Lightning Simulators

The lightning simulators are portable and range from large, full-threat simulators to smaller moderate-threat simulators. Indirect lightning effects can be evaluated to the requirements of MIL-STD-464 and FAA specifications. The simulators provide a significant range of tools to meet user requirements. Dielectric blocks are available to make a test stand for the platform being tested.

Near-Strike Lightning

The Near Strike Lightning (NSL) testing is conducted using two different test setups. The E-Field NSL pulser is a Marx stack capable of generating 2.5 mega volts (MV). An open-air spark gap of approximately 1 meter is used to simulate fields generated by NSL. The H‑Field NSL pulser is made up of a group of Marx generators designed to generate the proper waveforms and amplitudes. The 50 kA moderate-threat portable lightning simulator is composed of six Marx stages with each stage having a dedicated high voltage (HV) switch. Each simulator is set up to drive a plate wide enough to cover the entire test object.

Precipitation Static Simulator

The Precipitation Static (P-Static) simulator provides up to 400kv, 1.5ma charges to test items via high-voltage charging probes. The simulator is hand held and "sprays" the high-voltage charges onto small sections of the test aircraft. A portable VHF receiver and instrumentation equipment are used to investigate and record a baseline to use in correcting problem areas. The P-Static simulator is typically used in the shielded hangar, but testing capabilities are available for the flight line.

Electrostatic Discharge Simulators

The Electrostatic Discharge (ESD) simulators mimic the full threat effects of the natural human body ESD environment. The simulator is used to inject MIL-STD-464/MIL-STD-331 voltage waveforms into aircraft or weapons systems air launched ordnance. The 5 kV/25 kV simulator generates a waveform through a 500 ohm series resistance into a load of up to 5 microhenrys. A pulse can be produced every 3 minutes. A 300 kV ESD simulator is also available. This portable simulator produces the full threat effects of the natural helicopter vertical replenishment ESD environments. The simulator produces up to 300 kV through a 1-ohm series resistance into loads of up to 20 microhenrys.